I might feel anxious about starting a conversation with a stranger, but I love inspiring a room through public speaking. As a result, I’ve spoken at numerous conferences, and I’m often invited to speak at more.

Lately, I’ve been trying to figure out when and how to say no. I’ve been very good at saying yes in the past, and I’ve come across all sorts of great opportunities and met all sorts of great people that way. But presentations take time. I get three weeks of vacation each year. Visiting the Philippines or enjoying a staycation with W- and J- takes a two-week chunk. I sprinkle the days from the remaining week throughout my year to give myself short mental breaks or to take care of things I can’t easily reschedule. Conferences are great, but they take time too.

Planning a presentation is hard work. I almost always customize or re-create presentations extensively. I typically spend more than four hours preparing a presentation, much of it in the impossible-to-outsource task of organizing my thoughts and clarifying the key message. Some presentations take over my mind for a few days, using even my dream-time to sort out the content and the flow.

Then there’s the time it takes to actually give the presentation. There’s travel and the arrangements that need to be made. There’s delivering the presentation. If I want to make the most of a conference experience, I’d probably want to attend the other sessions and go to the evening events. Too many events close together, and the edges unravel. I misplace little things, I feel rushed, I stress out. I get myself through it with introvert breaks, but it’s still tough. And then there’s the time I need to catch up with work and life.

I’ve not been very good at saying no. The last time I tried to say no, I wasn’t very clear about it. I had offered to help find someone else—so I was still on the hook. That experience taught me a number of valuable lessons:

It’s easier to change a no to a yes than to change a yes into a no. Say no if there’s the least bit of doubt.

I can still create and deliver inspiring talk even if I’m annoyed with myself and the situation.

There are some opportunities that aren’t worth it for me to take.

The numbers are pretty crazy, too. Yes, I can speak to ninety, a hundred, two hundred people in a room—but I can share the same presentation online and reach more than 10,000 viewers. I want to reach much more people than those who pay the conference registration fee. With online presentations and blog posts, I can make things whenever I want to, without giving myself deadlines to worry about. My online work is a lot more searchable than most conferences’ archives. My estimated ROI is an order of magnitude larger, even discounting the value created in purely online presentations.

The key thing I like about conferences is the serendipity of learning from other people, of meeting interesting co-panelists and speakers and participants, of bumping into people over Twitter and in hallways. The Net is giving me more and more ways to do that on my own. It may be slower, but it still works.

So I’m beginning to understand why many speakers charge fees, and why authors have form letters that express their regrets. They’re making conscious decisions about how to spend their time and energy, and what to trade those for. I haven’t completely figured out how to handle speaking fees that with IBM. I love what I’m doing, so I’m not about to go off and become an independent speaker/consultant/writer/geek. (At least not yet!)

Some conferences I may still accept: the ones that are directly related to my work, perhaps, and from which I and my manager can see a clear benefit. Then they’re counted as work time, and there’s no confusion about whether something is IBM or not IBM. I’d be happy to let people explore other opportunities.

Over time, I may learn how to say no gracefully—and that will free me up to say yes to opportunities to deepen my understanding.